We're now told that this scintillating show of misery in a Kilburn bed-sit - working title, "One Mile Behind You," because that's where it was situated in relation to the old Hampstead portakabin theatre, round the corner from the new one - is the fastest-selling Hampstead play in living memory.
This is one of four plays Leigh wrote and directed for Hampstead between 1977 and 1988, and it followed the first of them, Abigail's Party, to which it bears a sort of perverse and distant relationship in being, well, mostly a party (though of course Abigail's was offstage) and a study in not so much suburban anomie as bedsit bonhomie; though the cheeriness is anything but cheerful.
The stage is littered with lager cans and gin bottles, a defiant gesture to the anti-boozing lobby, though no one is greatly enhanced or improved by the copious intake, so maybe Ecstasy was devised in the first place as cunning propaganda for Alcoholics Anonymous.
Stephen Rea, who played Mick in the original production, said that he used to consume seven cans of strong lager each night on stage, but remained totally in control; he also invented a back story for Mick (whose surname was McSweeney) who, he and Leigh decided, came from Macroom just outside Cork and had a brother who had a garage on the right-hand side of the road as you drove from Cork to Macroom.
A few months after Ecstasy closed, Rea was touring with Translations, the inaugural production of Field Day, the company he founded with playwright Brian Friel. He was driving from Cork to Macroom and, on the right-hand side of the road, he spotted a garage...called McSweeney's.
The other great story involved Jim Broadbent, who was also in that first cast, with Julie Walters. He was taken ill mid-performance one night and left the stage to go to the dressing room, where he passed out. Walters stopped the show and asked the audience if there was a doctor in the house. This being Hampstead, there was: 14 men stood up.
All of Leigh's new cast inhabit their roles as if, like the original cast, they had created them themselves in cahoots with Leigh, who always suggests that an actor starts with an idea of someone he or she knows, or knows about. I've seen several productions of Abigail's Party, and one or two of Ecstasy, and this is by far and away the best "new version" of an existing Leigh play, and establishes, I'd say, its classic status.
While it's true that, to a certain extent, Leigh worked in the theatre while struggling to gain a foothold in cinema, and that the cinema is where he prefers to work, it's also true that his body of work in the theatre is far more considerable than he's given credit for.
Two Thousand Years at the National Theatre was an impressive and highly amusing account of the impact of suddenly acquired religious orthodoxy in a secular household, and it will be fascinating to see what he comes up with later this year when he returns to create a new piece for Nicholas Hytner on the South Bank.
We know as much about it as he does at the moment: Lesley Manville will be in the cast, and the rest, he says "is floating around conceptually." And the next project he is planning to shoot, in 2013, is a film about the painter JMW Turner, whom Toby Jones recently played in Rebecca Lienkewicz's play that opened the new Arcola.
Contrary to wicked rumour, he has no plans to direct a West End musical for Cameron Mackintosh, though I bet we can't rule out a return to the Royal Shakespeare Company, where he once worked as an assistant director to both Peter Hall and Trevor Nunn.
And why not? The RSC's summer repertoire at Stratford-upon-Avon includes A Midsummer Night's Dream directed by Nancy Meckler, of a similar historic vintage as Mike Leigh - and it was her husband, David Aukin, who comissioned Ecstasy when he ran Hampstead Theatre with Michael Rudman in its most glorious period.